Japan’s venture into all-electric tankers is a vote of confidence in battery power
In a breakthrough for battery-powered shipping, Japanese plans to develop all-electric propulsion for bunker supply vessels operating in Tokyo Bay could ultimately lead to the country’s entire 7,000-strong fleet of domestic vessels being battery-driven.
Four giant corporations have thrown their weight into a project that has been dubbed e5 Lab: operator Asahi Tankers specialising in transporting oil-related products; project manager Exeno Yamamizu; Mitsubishi Corporation; and Mitsui OSK Lines (MOL), with others likely to join the venture as it unfolds.
Japanese classification society ClassNK is also involved and will advise on the overall design and electric propulsion for the debut vessel.
Though the ambitions are big, the project is starting small. Scheduled for launch around mid-2021, the first e5 ship will be a 60 m-long, 10.3 m-wide coastal tanker of 499 gross tonnes, with a 1,300 m3 cargo tank. The concept, a world first, was developed by Netherlands’ Groot Ship Design, a specialist in innovative cargo carriers.
The propulsion will likely include a pair of azimuth stern-mounted propellers capable of revolving 360° and a bow thruster. Main power will of course come from batteries, with a single generator set for back-up. Completing the all-electric specifications, the debut vessel will have automatic mooring with constant connectivity between ship and shore.
Constant connectivity is a fast-developing trend, whereby battery-powered ships are married with the latest suite of digitally-based technologies such as Rolls-Royce’s Autocrossing and Autodocking system. On the west coast of Norway, Fjord1’s double-ended ferries, Gloppefjord and Eidsfjord, work a short link between the towns of Anda and Lote entirely under battery power. With two 520 kWh batteries boosted by two 500 ekW Scania generators, each ferry can shift 120 cars and 249 passengers.
More remarkably, it only takes nine minutes for the ferries to be recharged in port via automatic charging stations located at the quayside. And because the ferries are equipped with a vacuum docking system that brings them alongside with a minimum of fuss, there is no need to run the engines and props at slow speeds to maintain station.
Until now, Norway has been leading the charge in all-electric and hybrid vessels. Ever since Ampere, the first all-electric ferry, was launched in 2014, the country has dominated in what might be called silent power. Nearly 40% of the world’s battery-propelled ships can be found in Norwegian waters. France occupies second spot on the rankings with nearly 20% of vessels being all-electric.
But Japan’s e5 Lab project could be a game changer. This is no surprise to Narve Mjøs, director of battery services and projects at class society DNV GL. “[Batteries] are a transformational technology in terms of electric vessels, but also for plug-in hybrid and hybrid ships,” he says, citing a string of benefits such as lower fuel consumption and costs, lower maintenance and, of course, lower emissions.
It is often forgotten though, he adds, that battery-powered ships are quieter, vibrate less and are generally safer. As the technology improves, there are further opportunities, for instance for harnessing waste heat to store energy.
The transformation has happened so rapidly that it caught many by surprise. In early 2019 there were about 200 all-electric or hybrid vessels in operation or under construction. In 2014, before Ampere was launched, there were none. As Mr Mjøs points out, it has taken about 20 years for the LNG fleet to get to approximately the same total.
Thus in a few short years the promise of electric propulsion has turned into reality. “Electric propulsion is the way of the future,” predicts Kongsberg Marine. “Technology is improving, range is increasing and the cost per kWh is steadily decreasing. This is impacting on the global ferry market [because] it makes battery-only and battery-hybrid systems ever more attractive.”
A new wave of forward-looking, engine-powered vessels that can be upgraded to all-electric will soon be launched under the Hanse Eco project. In a collaboration that combines Rhenus Logistics and operator Arkon Shipping among several other companies, the first of four short-sea vessels destined for European waters is taking shape in DaYang Offshore Equipment’s yard in China and is due for delivery in early 2021.
Although the initial propulsion will likely be provided by ABC Engines in Belgium, the vessel will be configured in anticipation of an eventual conversion to electric power.
“The ship will be battery-ready,” says Groot Ship Design. “The Hanse Eco design is believed to set a new standard for European short-sea shipping [and] will be used as a platform to implement future developments in making short-sea shipping more sustainable and environmentally friendly.” The design house sees batteries, hydrogen plus fuel cells, automation and other electrically-based technologies “becoming reality in years to come”.
However, while all-electric ferries are the obvious choice for short-haul work on fjords, inland and coastal waterways, hybrid propulsion is winning friends on bigger vessels plying longer routes and for offshore support vessels like the Norwegian Coastal Administration’s first hybrid vessel, the 44m-long Bøkfjord. Equipped with an 850 kWh battery pack along with three diesel-powered electrical generators, the vessel is used mainly for the building, operation and maintenance of lighthouses and other sea marks.
Golden Energy Offshore claims 20% savings in operational fuel from installing Kongsberg Maritime’s SAVe Energy battery system on two platform supply vessels, Orla and Frayja, in early 2019. “We were able to reduce total engine running hours by 43% in dynamic positioning operations,” reports Kongsberg data scientist Joakim Kjølleberg. Combined with operational fuel savings of 20% and shore connection when in port, both vessels are expected to post annual fuel savings equivalent to around 1,000 tonnes of CO2 and three tonnes of NOx.
The SAVe system is built around an energy storage unit that includes a liquid-cooled battery technology. A modular design, it can be scaled up or down according to demand. Its uses include peak shaving, the provision of spinning reserve, full power for offshore vessels, cruise ships, ferries, tugs and workboats.
The penny is dropping on the benefits of hybrid propulsion, especially in ports where authorities find themselves under mounting pressure to keep noise and pollution to a minimum. In fact, the environmental argument was one of the main inspirations behind the creation of the world’s largest plug-in hybrid vessel, Color Hybrid. Built by Ulstein Verft for Color Line operating out of the city of Sandefjord in Norway, the vessel was launched in mid-2019.
Because the local population insisted on a quiet, zero-emission vessel, Color Line sails in and out of port purely on batteries in what is generally a 30-minute exercise. It says a lot about the latest in battery power that the vessel is 160 m-long and can carry 2,000 passengers and 500 vehicles.
“At the moment there is still a misconception that batteries are only applicable for vessels sailing short regular routes, such as ferries,” says Mr Mjøs. “However, as more hybrid solutions are adopted, the industry is beginning to understand the possible applications, opportunities and benefits for vessels across multiple segments and operating parameters.”
Helsinki-headquartered Finnlines has also jumped into the hybrid space. The shipping group expects delivery in 2020 of the first of three ice-class 238 m-long ro-ro vessels from Jinling Shipyard that will feature four of Wärtsilä’s 1,250 kWh battery systems. These are powerful enough to propel a vessel with a cargo capacity of 5,800 lane metres plus 5,600 m2 of car decks and space for 300 TEU on weather deck.
“The vessel will operate on battery in harbour, guaranteeing zero emissions in port,” notes Wärtsilä. The batteries will be recharged during sailing.
And at the other end of the scale, Hurtigruten’s first hybrid cruise ship, Roald Amundsen, started operations in 2019. The batteries supplement the auxiliary engines for spinning reserve and peak shaving in a combination that, Hurtigruten reports, slashes fuel consumption by 20%.
One consequence of the trend towards all-electric and hybrid propulsion is the pressure to design more sea-friendly vessels that consume less power. Because power requirements have to be cut to the minimum to reduce the size, cost and charging needs of the batteries, particularly in pure battery ferries, ship designers say they are under pressure to come up with hull shapes that reduce underwater resistance and wear and tear on the propulsion system. A direct result is the demand for azipull thrusters.
Meantime Japan’s experiment with all-electric tankers will be closely watched. The partners in e5 Lab have set themselves a tight timetable that would see the Japanese fleet go all-electric by 2050.
How much for a kilowatt?
Shipping is the beneficiary of developments in batteries that began on terra firma. It was the automotive and consumer electronics industries that did the hard yards in the technology, particularly in the lithium-ion chemistry that underpins the Tesla and iPhone. While the energy giants stood on the sidelines, a handful of companies, most of them South Korean and Chinese, toiled on making batteries smaller, more powerful and cheaper.
As DNG VL senior engineer Benjamin Gully points out: “Multi-sector engagement is essentially fast-tracking development while driving down the cost of lithium-ion battery cells and making the technology increasingly attractive and accessible.”
The automotive sector has set itself a tough target for 2020 that, if it can be achieved, is certain to migrate to shipping. The goal is to cut the cost of a kilowatt of battery power to US$100, which is way down on just four years ago. Even if the car companies do not make it, most forecasters see cost per kilowatt continuing to fall over the next few years.
Mr Gully says: “The focus for ships’ batteries is often on performance -- a vessel requires enormous amounts of power which can easily shorten a battery’s lifetime.”
A ship’s battery will likely last about a decade, far less than an engine. And despite rapid advances in power, there is no battery on the horizon that can propel a deep-sea vessel for weeks on end. As Mr Gully explains, even if there was such a beast it would come at a cost of several times that of the vessel itself.
Maersk, which in late 2019 started trials with a 600 kWh containerised battery supplied by Trident Maritime Systems, would agree. “Propelling marine vessels with battery power alone is still years away from being a technically and economically viable option,” according to Maersk chief operating officer Søren Toft.
The trial, which is on Maersk Cape Town, is more about using batteries to improve the efficiency of onboard electrical systems, such as generators, in ways that reduce fuel consumption. But even that is progress compared with a few years ago.